Pressure-Sensitive Stylus Tip Detecting Cross-Axial Forces
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Solution Overview
Problem
Existing digitizer systems are not adequately sensitive to cross-axial forces applied to the writing tip, which can lead to inaccuracies in detecting contact pressure and transitions between hover and touch states.
Innovation Solution
A stylus with a sensor system that includes a compressible material surrounding the writing tip, capable of detecting tilting or bending through capacitive or resistive changes, allowing for sensitive detection of cross-axial forces and improving pressure sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional pressure sensors are used in the stylus, then axial force detection is achieved, but cross-axial force sensitivity is insufficient
Solution Approach 1:
The pressure sensing function is segmented into two independent sensor systems: one for axial force detection and another for cross-axial force detection. This segmentation allows each sensor to be optimized for its specific detection direction, improving overall measurement precision without compromising reliability
Solution Approach 2:
The invention adds cross-axial force detection capability to the traditional axial force sensing system. By introducing sensors that detect forces in the cross-axial direction (perpendicular to the stylus axis), the system transitions from one-dimensional to two-dimensional force detection, thereby improving measurement precision for contact pressure analysis
2Ease of operation
If the stylus tip is held at an angle during interaction, then natural writing posture is achieved, but cross-axial forces become significant and harder to detect
Solution Approach 1:
The cross-axial force sensors are pre-installed and calibrated within the stylus body before use. This preliminary preparation ensures that when the user adopts a natural angled writing posture, the system is already equipped to detect cross-axial forces without requiring any additional adjustment or complexity during operation
Solution Approach 2:
The cross-axial force sensors act as intermediaries that translate the complex multi-directional forces experienced during angled writing into measurable signals. These sensors mediate between the physical contact forces and the digital representation, making it easier to detect and interpret cross-axial force components
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the accuracy of detecting contact pressure and transitions between hover and touch states by monitoring bending and tilting of the writing tip, improving overall sensitivity to contact forces.
Implementation Method 1
at least one capacitive sensor to detect lateral and axial movements of the tip
Implementation Method 2
a deformable elastic material, e.g. a foam, arranged between a tip base and a ring, wherein the deformable elastic material may allow lateral movement of the tip, but provide elastic resistance such that the tip re-center within said ring when a force is removed
Implementation Method 3
a pressure sensor comprising a pressure-sensing plate, composed of a pressure-sensing resistive element between a movable disk-shaped actuator. The pressure sensor determines a magnitude of pressure by exploiting the property of a certain resistive material that changes resistance with the pressure it receives
Data Source
Figure 1A~1B
Figure 2
Figure 3A~4B
AI summary
A stylus includes a housing that extends along a longitudinal direction and includes an opening on one end, a tip that extends along the longitudinal direction and through the opening and a sensor configured to detect displacement of the tip in a direction perpendicular to the longitudinal direction.